Telephone transmitter



M. SENER. TELEPHONE TRANSMITTER. APPLICATION FILE'D MAR. I9, 1917.

Patented Mar. 7, 1922.

i 4 elementsy of the microphone.

unirse srmjrs :PATNT omer..

MICAEL SETTER, 0F CHICAGO, ILLINOIS, ASSIGNOR T0 AUTOMATIC ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION 0F ILLINOIS.

TELEPHONE TRANSMITTER,

maoaeas.

Specification of Letters Patent.

Patented Mar. 1922.

Application filed March 19, 1917. Serial No. 155,664. 'i

To all whom it may concern:

Beit known that 1, MICHAEL SETTER, a citizen of the United States of America, and a resident of Chicago, county of Cook, and State of'lllinois, have invented certain new and useful Improvements in Telephone Tranmiitters, of which the following. is a specification. v

My invention relates in general to telephone transmitters and has for its object to provide a transmitter structure in which certain of the parts, heretofore secured together by means of screw threads, are assembled by a press lit, and are held together solely by friction. This construction eliminates a large number of expensive screw machine' operations in building the transmitter and thereby greatly reduces the first cost of the nished article, without however in any way detracting from its durability or efficiency in operation.

The methods employed in carrying out the foregoing and other useful objects will he explained fully hereinafter, reference being had to the accompanying drawing, in which Fig. 1 is a back View of a complete transmitter, and Fig. 2 is a cross section on the line M-M of Fig. 1.

`Referring to the drawing the reference character 1 designates the usual mouthpiece screwed into a threaded opening in the face plate 2. The face plate 2 is provided with a rearwardly projecting circular rim 5 within` which iszheld by friction a heavy flanged ring4 4, seen most clearly in Fig. 1. The metal bridge piece 3 is formed integrally with the ring 4 and acts as a support for the This latter comprises the carbon electrodes 8 and 2i and the chamber 6` partially filled with the comminuted carbon 11. The rear electrode 8 is secured to a metal disk 7 which is provided with a central screw threa'ded stem 9.

The chamber 6 is simply a plain cup drawn vpreferably from brass, is lined with insulating material, and is provided with a central aperture in the bottom. rlihe stem 9 passes through this holeand a corresponding bushed aperture in the bridge 3, and the nut 10 is screwed down to clamp the whole together. llhe chamber 6 and the nut 10 are preferably insulated from the bridge 3 by means ofwashers 'of empire cloth.

The front electrode 21 is amxed to a metal disk 14 which has in front a tubular portion 16 and a central screw threaded stem 22. A mica diaphragm 18 fits over the tubular portion l16` and is held in place by a conical aluminum ring or Washer 15, which latter lits tightly over the tube 16 and is further secured by upsetting the edge of the tube. A metal clamping ring 12 fits tightly over the rim of the chamber 6 and the mica diaphragm is securely held between the' edge of the chamber and the said ring.` Y

The usual metal diaphragm 2O rests against an insulating ring 19 on the back of the faceplate 2, and has at the center a hole through which is passed the stem'22. By means of nuts 17 and 18 the stem 22 is rigidly secured to the diaphragm. The damping spring comprising two members 23 and 24 is attached to the ring 4 by means of screws 25 and 26. The extremities of these spring members 23 and 24 press against the diaphragm 20 as shown in Fig. 2, there being a felt washer interposed between the diaphragm and the end of each spring.

To enable the microphone to be connected in a telephone circuit, a screw 28 and a binding post 29 are provided, the latter being connected with the front electrode by means of a sleeved conductor one end ofv which. is clamped under the nut 17.

In assembling the various parts of the transmitter, the elements of the microphone should be mounted on the bridge before the latter is attached to the face plate. Thus the chamber or cup 6 and the rear electrode may rst be secured to the bridge by means of the nut 10 which is screwed down on the stem 9. The front electrode and the mica diaphragm are then` assembled, being held together as before mentioned by the aluminum ringI 15 which is forced on over the tube 16, the edge of the latter being then upset for further security. The proper quantity of granular carbon is then placed in the chamber and the mica diaphragm is placed in position across the top of the chamber. The clamping ring 12 is now forced on under ressure and grips the edge of the mica diaphragm between its flanged innerperiphery and the edge of the chamber. The bridge and the parts carried thereby being assembled, the nut 17 is screwed onto the chinery. After this is done the remaining' parts are assembled in any desired order to forni the finished transmitter.

lt will be observed from the foregoing that certain important parts of the transmitter, including the ring; el and face plate 2, the chamber d and clamping ring and the member' llwith the aluminum lo, are forced together preferably under considerable pressure, and when once assembled are practically inseparable by any ordinary means. ln addition to the great saying in the cost of manufacturer, this construction is of advantage in that it prevents tampering with the instrument when in service for die purpose of making adjustments. lit has been found impractible to attempt such adjustments in service and when they seem to be necessary it is intended that the transmitter bc shipped to the manufacturer, where special devices are provided for taking it apart.

It will be observed further that in my-improved transmitter the front or moi/*able electrode is mounted on a member lll which comprises in part ay tube or shell lll, and that the mica diaphragm. 13 is clamped between the member 14tand a conical aluminum washer l5, this method of construction being designed especially for the purpose of reducing the weight of the moving parts. rlifhis saving` in weight is of importance, for by reducing' the inertia of the nioring parts they are enabled to respond more readily to the vibrations caused by the impinging of the air currents on the main diaphragm, and the operation of the transmitter is therefore greatly improved.

Haring described. my invention what l considerato be new and desire to have protected'by Letters Patent will be pointed out in the appended claims.

l.Vhat l claim as my invention is zlln a. telephone transmit-ter, a face plate, and a microphone supporting bridge, the said bridge and face plate boing,1 forced together and held solely by friction.

2. :l transmitter structure involving a. face' plate provided, with a rearwardly ei;- tending,` rim, and a bridged ringl 'slightly larger in outside diameter than the inside diameter of said rim, the said ring* and face plate being forced together under pressure.

dal transmitter structure comprising a circular face plate and an electrode supporting' member, the two being adapted to be titted together to forni a frame for supporting,- the microphone' parts, and substantially smooth, concentric curved surfaces on the said member and face plate cooperatingt to hold the said member. and face plate rigidly together by the friction between theiriown surfaces.

4. ln a telephone transmitter, a microphone chamber, containing resistance vary-- ,toas-aa infr material means for closinf` one end of i said chamber, and a clampingn ring for holding said means in position, frictional surfaces substantially smooth, said ring being forced over the end of said chamber and being held in. place by friction between said surfaces.

5. ln a transmitter, an electrode having a cent-ral stem, a perforated diaphragm fitted over said stem, and a retaining washer forced over said stein and held. thereon by upsettingn the edge of the to thereby hold said diaphragm in place..

6. lo. a telephone transmitter, a. microphone, a support for said microphone consisting 'of a plurality of concentrically arranged parts assembled in pairs, substantially smooth lfrictional surfaces on said parts, the parts of each pair being forced together under pressure and held by friction between said surfaces.

7- A non-demountable transmitter structure comprising a plurality `ofeoncentrically arranged parts in pairs, the' parts of each pair being' permanently secured together by means of friction, and a microphone, said structure for supporting` said microphone.

8. ln a telephone transmitter, a movable electrode, a mounting for said electrode comprising a shell having a head to which the electrode is attached, a conica-l aluminum washer tightly llt-ted over said shell and held thereon by upsetting` the edgeof the shell, and a diaphragm clamped between-the said head and the said washer.

9. lln a telephone transmitter, a. tubular shell having a head portion closing one end, an electrode attached tosaid head, a conical aluminum. washer fitted over said shell and riveted thereon by upsetting the projecting edgre of the shell, and diaphragm clamped between the said head and the said washer.

l0, ln a telephone transmitter, a movable elect-rode and a support therefor', the said support comprising; a. member in the form of a tubular rivet, the said electrode being attached to the head thereof, an aluminum washer riveted on the tubular portion thereof, and a diaphragm clamped between the sai-d 'head portion and the said washer.

ll. ln a telephone transmitter, a microphonic cell comprisiup;i a cup containing resistance varying material, an electrode mounted in the bottom of said cup, a diaphragm, av ring1 for fastening said diaphragm over the! opening of said cup, said ring adaptedto over only the upper edge of the wall of the cup and so constructed as to tightly thereover, said ring forced over the rim of the cup in such a manner thatit may be removed Without changing its sha-pe.

Signed by me at Qhicaao. @ook county.. State of llllinois, this 15th day of March, lill?.

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